Conventional backpacks are generally configured with either an internal or external frame coupled to a compartment for carrying gear, such as, but not limited to clothing, food, water bottles and sleeping gear. Internal frame backpacks are generally more stable, but the weight or load of the gear in the load compartment should be selectively distributed to help improve the vertical and rotational stability of the backpack relative to a wearer. By way of example, one type of conventional internal frame backpack includes flexible stays arranged within frame material. The flexible stays may be arranged vertically, horizontally, or in some other direction in an attempt to transfer the load in the load compartment to the shoulder straps and the waist belt of the backpack.
Stabilizing the backpack on the wearer, maintaining a desired amount of ventilation between the backpack and the wearer, and providing a comfortable fit after the backpack has been loaded and strapped onto the wearer has always been some of the primary challenges in designing and configuring a backpack. In some environments, where heavy backpack loads are required or where the backpack is to be worn with other gear, such as body armor in a military environment, the above-identified design challenges become even more difficult to overcome. By way of example, backside armor is generally curved or contoured to at least somewhat conform to the general shape of a soldier's back. Conventional backpacks tend to ride on and slide relative to the backside armor. Under heavy load conditions, such as when the backpack includes a substantial amount of weight (e.g., food, clothing, ammunition, communications gear, etc.), the backpack may become unstable relative to the backside armor. To stabilize the backpack, soldier's often have to highly tighten the waist belt, which in turn presses the backside armor into the soldier's back and entraps body heat.
U.S. Patent Publication No. 2005/02025634 to Han describes cushion pads for backpacks. Each cushion pad includes a porous filter which is placed inside the net fabric to dissipate heat to the atmosphere, and a sheet which is made of a material such as polyurethane and layered on a surface of the porous filter. The sheet is inserted along with the porous filter into a space defined between the net fabric and the cloth of the backpack. Han suggests that the cushion pads provide improved ventilation and elasticity to the backpack and the shoulder straps of the backpack.
U.S. Patent Publication No. 2004/0134955 to Williams describes a ventilation system that may be attached to a conventional backpack. The ventilation system elevates the backpack, hydration pack, fanny pack, or the like off the wearer's skin. The ventilation system includes pliable supports that provide for pressure relief and good ventilation between a wearer's back and the conventional backpack. Williams suggests that the purpose of the invention is to support and elevate the backpack off of the wearer's skin or other bodily part in order to reduce the pack's surface area in contact with the wearer, thusly increasing ventilation and exposed wearer's body surface area to maximize cooling, therefore reducing perspiration and water consumption, while increasing performance, comfort, and physical and mental endurance.
Japanese Patent No. JP09252840 by Shigeharu describes a back panel and cushioning system that includes a back panel that couples to the backpack. The back panel substantially over a width of the wearer's back and includes left and right edges that are curved in a direction away from the back. Cushioning devices are coupled to the left and right edges and generally extend from an upper edge to a lower edge of the back panel. Shigeharu suggests that the space created between the back panel and the wearer's back because the cushioning devices offset the backpack from the wearer's back provides improved ventilation.